| 摘要 |
Methyl substituted aromatic compounds are made by contacting a diaryl methane compound in the presence of hydrogen with a catalyst of high melting point having hydrogenating activity. The catalyst may be a compound of a metal of Groups VI-VIII of the periodic classification having atomic number of at least 24, e.g. one or more of the sulphides of chromium, molybdenum, tungsten, manganese, iron, cobalt or nickel, or may be activated carbon. The reaction is carried out at 400-450 DEG C. under a pressure of 250-275 lb./sq. in. Examples are concerned with preparing (i) p-, o- and m-xylenes by hydrocracking ditolylmethane or the product obtained by alkylating toluene with formaldehyde; (ii) durene, with small quantities of isodurene and prehnitene by hydrocracking recrystallized bis-(2,4,5-trimethylphenyl) methane obtained by alkylating pseudocumene with formaldehyde; (iii) pentamethylbenzene (m.p. 53 DEG C.) by hydrocracking bis - (2,3,4,6 - tetramethylphenyl) methane obtained by alkylating with formaldehyde a mixture of isodurene, prehnitene and unseparated durene obtained by the procedure (ii); (iv) a 2,6- and 2,7-dimethylnaphthalene mixture by hydrocracking a mixture of bis-(6-methylnaphth-2-yl), bis-(7-methylnaphth-2-yl) and 6,71 - dimethyl - dinaphth - 2 - yl methanes obtained by alkylating b -methylnaphthalene with formaldehyde; (v) toluene by hydrocracking diphenylmethane. Other groups which may be present in the diaryl methane starting material should be non-reactive under the conditions of the process for severance of one of the aryl groups from the methylene carbon bonded to the two aryl groups. Examples of other diarylmethane compounds which may be used as starting materials and which may be prepared by alkylation of the corresponding aryl compounds with formaldehyde are: di-b -5,6,7,8-tetrahydronaphthylmethane from tetrahydronaphthaline, p-p1-dichlorodiphenylmethane from chlorobenzene, p - p1 - diaminodiphenylmethane from aniline, N,N,N1,N1-tetramethyl-p, p1-diaminodiphenylmethane from dimethylaniline, bis-(o-methoxyphenyl) methane and bis-(p-methoxyphenyl) methane from methylphenyl ether, bis-(2,4-dimethylphenyl) methane from m-xylene, dib -naphthylmethane from naphthalene, and bis(2 - hydroxy - 3,5 - dimethylphenyl) methane from 2,4-dimethylphenol.
|
